In recent years, the Universal Serial Bus (USB) provides a universal interface for the connection and control between computers and various peripheral devices. Generally, the computer acts as a USB host device while the peripherals do as USB slave devices. The USB host provides electric power to the USB slaves, and transmits as well as receives data.
The specification of USB on the go (OTG) is provided for the connection and control among different types of peripheral devices. The main purpose of the emerging USB OTG specification is to allow two different USB peripheral devices connect to each other without via the computer and the host and slave relationship can be altered when necessary. There are four connecting pins in a traditional USB device, while the USB OTG which is required in an USB device complying with the USB OTG specification needs an additional ID pin for identifying the USB device as a host or a device.
According to prior art, there is a common issue of device burnt down or damaged due to power confliction between a device and an external device are coupled to each other without pre-determining the host-device relationship therebetween. Besides, the USB device connector or host connector utilized between two USB devices has to be employed to determine which one of the two USB devices is a USB host while the other one a USB device, so as to further manage the connection and control of the two USB devices, if anyone of the two USB devices does not comply with the USB OTG specification (i.e., lacking either USB OTG chip or ID pin or both).
Therefore, a non-USB OTG device according to the prior art needs to be equipped with different USB connectors to determine whether the device is a USB host or a USB device when being connected with other USB devices. There exists neither a universal connector nor an auto-detection method for such a purpose.